package com.atguigu.springcloud.lb;

import org.springframework.cloud.client.ServiceInstance;
import org.springframework.stereotype.Component;

import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;


@Component
public class MyLB implements  LoadBalancer{
    private AtomicInteger atomicInteger=new AtomicInteger(0);

    //这个方法的作用是获取访问的次数，
    public final int getAndIncrement(){
        int current;
        int next;
        do {
            current=this.atomicInteger.get();
            next=current>=Integer.MAX_VALUE?0:(current+1);
        }while(!this.atomicInteger.compareAndSet(current,next));
        System.out.println("第"+next+"次访问next值！");
        return next;
    }
    //这个方法的作用是通过上面的getAndInstance方法的next值对所有的服务实例进行取余,决定是启用哪个服务器
    @Override
    public ServiceInstance instance(List<ServiceInstance> serviceInstances) {
        int index=getAndIncrement() % serviceInstances.size();
        return serviceInstances.get(index);
    }
}
